Jaybird180
Final Approach
Nothing saying you can't outfit a G650 with aerial refueling and a number of other features.
Or, change the mission requirements.
That ain't happening. There's also a lot of classified equipment on board that I'm sure needs space and takes up weight. I don't know what the MGW of a G650 is but I'm pretty certain it can't come close to a B-747.
But since this is satire anyhow....why not!